Mastercard Incorporated (MA) vs Merck & Co., Inc. (MRK)

Mastercard Incorporated is the world’s second-largest payment processor, handling nearly $11 trillion in payment volume during 2025. The company operates in more than 200 countries and territories and processes transactions in over 150 currencies worldwide.

Merck & Co., Inc. develops pharmaceutical products across multiple therapeutic areas, including cardiometabolic disorders, oncology, and infectious diseases. In cancer treatment, its immuno-oncology portfolio, led by Keytruda, represents a significant driver of total revenue. The company also maintains a strong vaccines business focused on preventing pediatric illnesses, alongside Gardasil for human papillomavirus. In addition, Merck markets animal health products. Geographically, 47% of the company’s sales come from its U.S. human health segment, which includes pharmaceuticals and vaccines.